From: Rusty Russell <rusty@xxxxxxxxxxxxxxx> Date: Thu, 17 May 2012 13:02:53 +0930 > On Wed, 16 May 2012 10:57:13 +0300, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: >> __napi_schedule might raise softirq but nothing >> causes do_softirq to trigger, so it does not in fact >> run. As a result, >> the error message "NOHZ: local_softirq_pending 08" >> sometimes occurs during boot of a KVM guest when the network service is >> started and we are oom: >> >> ... >> Bringing up loopback interface: [ OK ] >> Bringing up interface eth0: >> Determining IP information for eth0...NOHZ: local_softirq_pending 08 >> done. >> [ OK ] >> ... >> >> Further, receive queue processing might get delayed >> indefinitely until some interrupt triggers: >> virtio_net expected napi to be run immediately. >> >> One way to cause do_softirq to be executed is by >> invoking local_bh_enable(). As __napi_schedule is >> normally called from bh or irq context, this >> seems to make sense: disable bh before __napi_schedule >> and enable afterwards. >> >> Reported-by: Ulrich Obergfell <uobergfe@xxxxxxxxxx> >> Tested-by: Ulrich Obergfell <uobergfe@xxxxxxxxxx> >> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> ... > Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx> Michael, you're best to submit this directly to Linus as I just made what I hope is my last push to him for 3.4 today. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
